Ketotifen, classified within the group of cycloheptothiophenones, is notable for its strong antihistamine effects. It is specifically categorized as a non-bronchodilating anti-asthma medication. The mechanism by which ketotifen operates is centered around its ability to inhibit the release of histamine and other mast cell mediators. This is achieved through the blocking of histamine H1 receptors and the inhibition of the phosphodiesterase enzyme. As a result of these actions, there is an increase in the levels of cyclic adenosine monophosphate (cAMP) within mast cells. Additionally, ketotifen can suppress the effects of TAF (platelet-activating factor).